This invention relates to an original carrier for use with an image forming device for holding an original document or other item to be copied by the device. The invention is particularly directed to use with a reciprocative type image forming device.
Recently, there has been a demand for miniaturization of copying machines. To meet this demand, a reciprocating original carrier has been developed. An example of this conventional holder is shown in FIG. 1. As shown, a heavy metal plate frame 3 is reciprocally moved on guide rails (not shown) provided on the upper portion of the copying machine's main body 1. A square opening 6 is provided on frame 3 and a glass plate 4 is attached within the opening. A cover 2, positioned at one end of frame 3, is mounted through hinge 5 so that it can be easily opened and closed to retain the original. Prior to copying, cover 2 is raised so that the original can be positioned, image side down, on glass plate 4. The cover is then closed and frame 3 begins reciprocating in the direction shown by operation of a proper drive member.
In this conventional design, frame 3 must support glass plate 4 and cover 2. Consequently, frame 3 must have a rigidity and weight to permit such support while continuous reciprocative action occurs. As a result, it has been necessary to employ a fairly heavy frame which, concomitantly requires a large driving force to produce the reciprocative action. Further, the drive system must be designed to accomodate this additional force while requiring additional components for effective operation. A further disadvantage is that due to the necessary usage of frame 3, compactness is not provided. The presence of a frame surrounding glass plate 4 necessarily limits the size of the holder. In addition, the fabrication of such carriers are complex requiring a number of parts.
Some prior art reciprocative type copying machines having a metal frame along one side does not overcome these problems. The design shown in U.S. Pat. No. 4,129,374, for example, utilizes a metal U-shaped frame fixed to one side of the glass plate. This design, however, also requires the use of a cover frame which is fixed to the metal frame. This design, therefore, requires the use of a heavy drive system to accomodate the metal frame and the cover frame.